Gas-filled incandescent electric lamp with filament having increased strength



Patented Mar. 29, 1927. I

UNITED STATES 1,622,826 PATENT OFFICE.

DANIEL SNYDER GUSTIN, OF EAST ORANGE, NEW JERSEY, ASSIGNOB TO WESTING-HOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

GAS-FILLED IN CANDESCENT ELECTRIC LAMP WITH FILAMEN T HAVING HI'CBEASEDSTRENGTH.

No Drawing."

This application is a continuation-in-part of my copending application,Serial No. 639,460, filed May 16, 1923, gas-filled incandescent lampsand getters therefor and assigned to the Westinghouse Lamp Company'.

This invention relates to mcandescent candescent electric lamp of such acharacter,

that the crystal structure of the metal filament is substantiallyimproved.-

A further object of my invention is the employment of a getter in agas=filled incandescent electric lamp, which getter is adapted toefiiciently remove moisture and thereby make it possible to employ acold exhaust for such lamps or exhaust at any temperature.

A still further object of my invention is the manufacture of gas-filledelectric lamps, into the bulbs of which is introduced diphenyl aminewith the gas filling.

Other objects and advantages of the invention will become apparent asthe description proceeds.

In my aforementioned copending application, of which the presentapplication is a continuation-in-part, I have described getters whichmay be used, either applied to the filaments of lamps or introduced withthe gas fillin thereof, whereby the necessity for heating t e bulbsthereof during exhaustion is obviated, because such materials are veryeflicient for removing moisture as well as other materials, such asoxygen and nitrogen.

Although benzidine, or di-para-diaminodiphenyl, (NIL) 10 11,) has beenfound to be the preferred organic compound for introduction on thefilament of the lamp, whereby cold exhaust may be utilized, yet I havefound, that when using diphenyl amine, NH(G H,) I effect, in addition, a

Application filed November 29, 1924. Serial No. 752,942.

very desirable result, in that the strength of the filament is verymaterially increased, and the lumen maintenance during life is alsoimproved.

I preferably introduce avaporizable material such as diphenyl amine,which is a preferred example of an organic getter for increasingfilament strength, with the gas filling for-the 'lampyet, if desired,similar materials, having ower vapor pressures, might be applieddirectly to the filament, b means of a vehicle such as water or alcohoin the form of a solution or suspension.

My invention will better be understood by the following more detaileddescription thereof.

I preferably place my getter, in solid form, in a tube and allow thefilling gas to pass throughthe tube and over or thru the getter.- Thevapor tension ofmy preferred getter, diphenyl amine, is such, that asufficient proportion is taken up by the inert filling gas, whensubstantially saturated therewith, to act onthe metal filament to thedesired extent. The bulb of the lamp is evacuated, either hot or coldand filled with said gas, either with or without preliminary flushingwith nitrogen. The lamp is then tipped off and the filament flashed.

In order to show more clearly the improved results which may be securedby using diphenyl amine as a getter in metal filament, gas-filled,incandescent, electric iarlnps, the following results are tabulated eow:

' Average of life tests.

Burnout S andard 111a spec. life With getter 1,382 Hm. 2,642 Hrs. Wthout getter 1,266 HIS. 1,946 Hrs.

Average per cent of initial lumens during life.

I Per'cent. With getter 97. 4 Without getter 93. 8

The foregoing results clearly indicate that on bump test, the strengthof the refractory metal or tungsten filament shows a material increase,both immediately after seasoning and after burning over night at 115% ofnormal or rated voltage.

From the life test results, it will be seen that by using this getter,the burnoutlife is substantially lengthened as well as the standardspecification life, which is a calculated life, based on efiiciency aswell as actual life, and the average percent of initial lumens duringlife is materially increased;

Although, as aforementioned, it is preferred to introduce diphenylamine, or its equivalent, with the gas filling, yet equiva-.

lent materials or substitutes. having lower vapor pressures, so that\they would not evaporate from the filament during exhaust, might beapplied directly upon the filament by dipping, spraying or otherwiseapplying before mounting. For example, a weak solution, such as a 2%alcoholic solution may be used for this purpose. The mounted filamentmay be sealed into the lamp bulb in the usual manner, the lamp exhaustedeither hot or cold, after which the desired gas filling may beintroduced either with or without a preliminary flushing with nitrogen.The lamp may then be tipped off, the filament flashed, and it will befound that not only does the strength of the filament increase, but theother desirable results aforementioned are obtained.

Although diphenyl amine has been mentioned as the preferred material fora getter, according to my invention, I do not wish to be restrictedthereto, as various other materials, of the same character,substantially free from oxygen or oxidizing material, may be used. Forexample, it should be noted that ortho-amino-diphenyl, NH C I-LC H anisomer of diphenyl amine, although not as desirable as diphenyl amine,may be em ployed, with good results.

The aforegoing invention has proved so successful that it is now incommercial use on a large scale.

Although I have described what is now considered a preferred embodimentof my invention, it is to be understood that the same is merelyillustrative and that other modifications may be made within thespiritand scope of the appended claims.

What is claimed is:

1. An incandescent, metallic filament electric lamp of the gas-filledtype, containing.

an organic material improving the resistance of the filament to shock.

2. An incandescent electric lamp of the gas-filled type, containing agetter composed of diphenyl amine.

3. An incandescent electric lamp of the gas-filled type, containing agas filling impregnated with diphenyl amine.

4:. An incandescent electric lamp of the gas-filled type, comprising anon-carbon 'resistance of metal filaments to shock, comprising diphenylamine.

8. The method of manufacturing incandescent electric lamps of thegas-filled type, comprising sealing a filament into a bulb, exhaustingthe bulb cold and replacing the exhausted air by an inert gascontaining.

diphenyl amine.

9. The method of increasing the strength of refractory metal filamentsin incandescent electric lamps of the gas-filled type, comprisingintroducing an inert gas filling substantially saturated with diphenylamine.

In testimony whereof, I have hereunto subscribed my name this 28th dayof November 1924.

DANIEL SNYDER GUSTIN.

